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Texas Instruments TM990/101 M (and its Mystery Chassis)


Nov 18, 2003
Landenberg, PA USA
I have a TI chassis I have been unable to locate documentation. Can anyone help shed some light on the following. .?

The card chassis:
Within a Steel 4-slot Texas Instruments card chassis the size of a shoe box are four Texas Instruments cards manufactured in the US. These cards resemble a regular s-100 card but the 100 contacts are off center, to the left when viewing the component side with the 100 pin side down. Printed on the chassis is Assy No. is 0994676-0001 and Diag No. 0394677. I do not have a power supply, but I assume you'd attach to terminals on the back of the chassis somehow (?).

Inside are 4 cards.
Two cards are similar are RAM/EPROM cards with 32K in each (8 x 4 rows I assume = 32K ?). The RAM is a mix of TMS 4045-30NL, TMS 4045-30, and TMS 4014NL. There are no Eproms installed, but there are two rows of empty slots on the card. Each card has 8 dip switches.

The third card is labeled TM990/101 M. This appears to be a processor/modem/term card with a TMS 9900JL EP7840 ceramic/gold processor, and a TMS 9901NL chip, etc. The card has two 25 pin female connectors apparently for serial i/o. An earlier model's users guide:

The fourth card is labeled "universal prototype board TM990/512". This card may be newer than the rest and has an Intel P8253 chip (date = '80). There is extensive wiring on the back of the card, it could be for a disk drive, I don't know. The card has 2 40 pin flat connectors.

I am hoping someone can point me in the direction for a TM990/101 M Users Guide or documentation about the chassis and/or individual components. I can post pictures by request.